We sometimes talk about Linux as if it were one, single operating system, but of course, it really comes in hundreds of different flavors. In fact, one of the strengths of open source software is that developers can (and do) customize the code to meet a variety of unique needs.

In this article, we'll take a look at 50 of the most well-known distributions of the Linux OS. If you've been using Linux for a while, you're probably familiar with the major distributions, but you might find some others you haven't encountered that are worth checking out.

The list is organized into several different categories. The "major" distributions come first, followed by distros based on Ubuntu, Debian, Red/Hat Fedora, Mandriva, Slackware, Arch and Gentoo. Next come some distros that are optimized for cloud computing, some very lightweight distributions, some that are designed to look as much like Windows as possible and finally, some notable distros that didn't seem to fit into any other category. Of course, some distributions could fit into more than one category, but we tried to place them where they seemed to fit most naturally.

Also, in limiting ourselves to the fifty, we undoubtedly left off some noteworthy Linux distributions. If you'd like to nominate one (or more) that you think should have been included, please free to use the comments section below.

Major Linux Distros

Canonical's Ubuntu is probably the most popular Linux distribution in the world for desktop computers. Recently released version 11.04 offers a new Unity interface. It's available in desktop, server and cloud editions, as well as in several variations that are included lower on this list.

The Red Hat company calls itself "the world's open source leader," and its server version of Linux is a particular favorite with enterprises. It's available only with a paid subscription, but does have a community version--Fedora.

This community-owned project provides the code base for a lot of other Linux distros, including Ubuntu, DSL, MEPIS and many others. It can be used for desktops or servers and all versions are completely free.

Novell's version of Linux for enterprises is available only with a paid subscription (although you can download the very similar openSUSE for free). It claims to be "the most interoperable platform for mission-critical computingacross physical, virtual and cloud environments."

Linux Mint boasts that it is the fourth most popular operating system for home users, behind Windows, OS X, and Ubuntu. It has a reputation for being very easy to use and it includes about 30,000 packages.

First released in 2002, Gentoo boasts "extreme configurability, performance and a top-notch user and developer community." It uses the Portage package management system, which currently includes more than 10,000 different applications.

8. Arch Linux

Arch is definitely not for Linux newbies, but its simple design makes it a favorite among long-time Linux users who are comfortable with the command line. By default, it installs a minimal base system but provides plenty of options for customization.

Fedora is the free, community version of RedHat's popular Linux distribution, and it's been called "the best place to track what's on the leading edge of Linux and open source software." In addition to the standard desktop download, it's available in a number of specialized versions, which it calls "spins."

The free, community version of Novell's SUSE distro, openSUSE calls itself "Linux for open minds." It can be used on a desktop, laptop or server and can be installed or run live from a CD or USB drive.

Designed for use on netbooks, EasyPeasy boasts millions of users in more than 166 countries. It was built to support social networking and cloud computing, and it offers very low power consumption for longer battery life on mobile devices.

Zentyal is a Ubuntu-based small business server that can act as a gateway, infrastructure manager, unified threat manager, office server and/or unified communication server. It's available as a free download or in paid, supported versions.

Supported by the Free Software Foundation, gNewSense is based on Ubuntu with a few changes, like the removal of non-free firmware. The name started as a pun on "Gnu" and "nuisance" and is pronounced guh-NEW-sense.

Built for new Linux users who need something that's even easier to use than Ubuntu, Pinguy OS makes it easy to find and use the programs average users need most often. It's also available in a DVD version for $5.99.